<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        body>div{
            width: 400px;
            height: 400px;
            background-color: red;
        }
        #top_div{
            height: 35px;
            background-color: #0aa1ed;
            border-radius: 2px;
        }
        #bot_div{
            background-color: yellow;
        }
        div>div{padding-left: 10px}
        p{
            background-color: green;
            margin: 0;
            padding: 0;
        }

        p{
            margin: 30px;
        }

    </style>
</head>
<body>
<div>
    <div id="top_div">
    </div>
    <div id="bot_div">
        <p>你好世界</p>
    </div>

</div>

</body>
</html>